1 // SPDX-License-Identifier: GPL-2.0 2 3 //! The `kernel` crate. 4 //! 5 //! This crate contains the kernel APIs that have been ported or wrapped for 6 //! usage by Rust code in the kernel and is shared by all of them. 7 //! 8 //! In other words, all the rest of the Rust code in the kernel (e.g. kernel 9 //! modules written in Rust) depends on [`core`], [`alloc`] and this crate. 10 //! 11 //! If you need a kernel C API that is not ported or wrapped yet here, then 12 //! do so first instead of bypassing this crate. 13 14 #![no_std] 15 #![feature(arbitrary_self_types)] 16 #![feature(coerce_unsized)] 17 #![feature(dispatch_from_dyn)] 18 #![feature(inline_const)] 19 #![feature(lint_reasons)] 20 #![feature(unsize)] 21 // Stable in Rust 1.83 22 #![feature(const_maybe_uninit_as_mut_ptr)] 23 #![feature(const_mut_refs)] 24 #![feature(const_ptr_write)] 25 #![feature(const_refs_to_cell)] 26 27 // Ensure conditional compilation based on the kernel configuration works; 28 // otherwise we may silently break things like initcall handling. 29 #[cfg(not(CONFIG_RUST))] 30 compile_error!("Missing kernel configuration for conditional compilation"); 31 32 // Allow proc-macros to refer to `::kernel` inside the `kernel` crate (this crate). 33 extern crate self as kernel; 34 35 pub use ffi; 36 37 pub mod alloc; 38 #[cfg(CONFIG_BLOCK)] 39 pub mod block; 40 mod build_assert; 41 pub mod cred; 42 pub mod device; 43 pub mod device_id; 44 pub mod driver; 45 pub mod error; 46 #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] 47 pub mod firmware; 48 pub mod fs; 49 pub mod init; 50 pub mod ioctl; 51 pub mod jump_label; 52 #[cfg(CONFIG_KUNIT)] 53 pub mod kunit; 54 pub mod list; 55 pub mod miscdevice; 56 #[cfg(CONFIG_NET)] 57 pub mod net; 58 pub mod page; 59 pub mod pid_namespace; 60 pub mod prelude; 61 pub mod print; 62 pub mod rbtree; 63 pub mod security; 64 pub mod seq_file; 65 pub mod sizes; 66 mod static_assert; 67 #[doc(hidden)] 68 pub mod std_vendor; 69 pub mod str; 70 pub mod sync; 71 pub mod task; 72 pub mod time; 73 pub mod tracepoint; 74 pub mod transmute; 75 pub mod types; 76 pub mod uaccess; 77 pub mod workqueue; 78 79 #[doc(hidden)] 80 pub use bindings; 81 pub use macros; 82 pub use uapi; 83 84 #[doc(hidden)] 85 pub use build_error::build_error; 86 87 /// Prefix to appear before log messages printed from within the `kernel` crate. 88 const __LOG_PREFIX: &[u8] = b"rust_kernel\0"; 89 90 /// The top level entrypoint to implementing a kernel module. 91 /// 92 /// For any teardown or cleanup operations, your type may implement [`Drop`]. 93 pub trait Module: Sized + Sync + Send { 94 /// Called at module initialization time. 95 /// 96 /// Use this method to perform whatever setup or registration your module 97 /// should do. 98 /// 99 /// Equivalent to the `module_init` macro in the C API. 100 fn init(module: &'static ThisModule) -> error::Result<Self>; 101 } 102 103 /// A module that is pinned and initialised in-place. 104 pub trait InPlaceModule: Sync + Send { 105 /// Creates an initialiser for the module. 106 /// 107 /// It is called when the module is loaded. 108 fn init(module: &'static ThisModule) -> impl init::PinInit<Self, error::Error>; 109 } 110 111 impl<T: Module> InPlaceModule for T { 112 fn init(module: &'static ThisModule) -> impl init::PinInit<Self, error::Error> { 113 let initer = move |slot: *mut Self| { 114 let m = <Self as Module>::init(module)?; 115 116 // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. 117 unsafe { slot.write(m) }; 118 Ok(()) 119 }; 120 121 // SAFETY: On success, `initer` always fully initialises an instance of `Self`. 122 unsafe { init::pin_init_from_closure(initer) } 123 } 124 } 125 126 /// Metadata attached to a [`Module`] or [`InPlaceModule`]. 127 pub trait ModuleMetadata { 128 /// The name of the module as specified in the `module!` macro. 129 const NAME: &'static crate::str::CStr; 130 } 131 132 /// Equivalent to `THIS_MODULE` in the C API. 133 /// 134 /// C header: [`include/linux/init.h`](srctree/include/linux/init.h) 135 pub struct ThisModule(*mut bindings::module); 136 137 // SAFETY: `THIS_MODULE` may be used from all threads within a module. 138 unsafe impl Sync for ThisModule {} 139 140 impl ThisModule { 141 /// Creates a [`ThisModule`] given the `THIS_MODULE` pointer. 142 /// 143 /// # Safety 144 /// 145 /// The pointer must be equal to the right `THIS_MODULE`. 146 pub const unsafe fn from_ptr(ptr: *mut bindings::module) -> ThisModule { 147 ThisModule(ptr) 148 } 149 150 /// Access the raw pointer for this module. 151 /// 152 /// It is up to the user to use it correctly. 153 pub const fn as_ptr(&self) -> *mut bindings::module { 154 self.0 155 } 156 } 157 158 #[cfg(not(any(testlib, test)))] 159 #[panic_handler] 160 fn panic(info: &core::panic::PanicInfo<'_>) -> ! { 161 pr_emerg!("{}\n", info); 162 // SAFETY: FFI call. 163 unsafe { bindings::BUG() }; 164 } 165 166 /// Produces a pointer to an object from a pointer to one of its fields. 167 /// 168 /// # Safety 169 /// 170 /// The pointer passed to this macro, and the pointer returned by this macro, must both be in 171 /// bounds of the same allocation. 172 /// 173 /// # Examples 174 /// 175 /// ``` 176 /// # use kernel::container_of; 177 /// struct Test { 178 /// a: u64, 179 /// b: u32, 180 /// } 181 /// 182 /// let test = Test { a: 10, b: 20 }; 183 /// let b_ptr = &test.b; 184 /// // SAFETY: The pointer points at the `b` field of a `Test`, so the resulting pointer will be 185 /// // in-bounds of the same allocation as `b_ptr`. 186 /// let test_alias = unsafe { container_of!(b_ptr, Test, b) }; 187 /// assert!(core::ptr::eq(&test, test_alias)); 188 /// ``` 189 #[macro_export] 190 macro_rules! container_of { 191 ($ptr:expr, $type:ty, $($f:tt)*) => {{ 192 let ptr = $ptr as *const _ as *const u8; 193 let offset: usize = ::core::mem::offset_of!($type, $($f)*); 194 ptr.sub(offset) as *const $type 195 }} 196 } 197 198 /// Helper for `.rs.S` files. 199 #[doc(hidden)] 200 #[macro_export] 201 macro_rules! concat_literals { 202 ($( $asm:literal )* ) => { 203 ::core::concat!($($asm),*) 204 }; 205 } 206 207 /// Wrapper around `asm!` configured for use in the kernel. 208 /// 209 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 210 /// syntax. 211 // For x86, `asm!` uses intel syntax by default, but we want to use at&t syntax in the kernel. 212 #[cfg(any(target_arch = "x86", target_arch = "x86_64"))] 213 #[macro_export] 214 macro_rules! asm { 215 ($($asm:expr),* ; $($rest:tt)*) => { 216 ::core::arch::asm!( $($asm)*, options(att_syntax), $($rest)* ) 217 }; 218 } 219 220 /// Wrapper around `asm!` configured for use in the kernel. 221 /// 222 /// Uses a semicolon to avoid parsing ambiguities, even though this does not match native `asm!` 223 /// syntax. 224 // For non-x86 arches we just pass through to `asm!`. 225 #[cfg(not(any(target_arch = "x86", target_arch = "x86_64")))] 226 #[macro_export] 227 macro_rules! asm { 228 ($($asm:expr),* ; $($rest:tt)*) => { 229 ::core::arch::asm!( $($asm)*, $($rest)* ) 230 }; 231 } 232